[Sanitizers] ASan/MSan/LSan allocators set errno on failure.

Summary:
ASan/MSan/LSan allocators set errno on allocation failures according to
malloc/calloc/etc. expected behavior.

MSan allocator was refactored a bit to make its structure more similar
with other allocators.

Also switch Scudo allocator to the internal errno definitions.

TSan allocator changes will follow.

Reviewers: eugenis

Subscribers: llvm-commits, kubamracek

Differential Revision: https://reviews.llvm.org/D35275

llvm-svn: 308344